Thursday, 26 March 2015

Is there an Anthropocene? This question is being debated currently
and a report is to be published in 2016 on whether a geological epoch created
by the transformative activities of Homo
sapiens should be defined, and what should mark its beginning. According to
Richard Monastersky [1]:

A committee of researchers is
currently hashing out whether to codify the Anthropocene as a formal geological
unit, and when to define its starting point.. .. The push to formalize the
Anthropocene upsets some stratigraphers.. ..One major question is whether there
really are significant records of the Anthropocene in global stratigraphy.. ..Some
researchers argue that it is too soon to make a decision – it will take
centuries or longer to know what lasting impact humans are having on the
planet.

Monastersky then quotes from Erle Ellis, a Geographer at the
University of Maryland:

"We should set a time,
perhaps 1000 years from now, in which we would officially investigate this.. ..Making
a decision before then would be premature."

Discussion about the Anthropocene thus reflects a typical debate
among scientists and other academics having different views of what marks a
definable stratigraphic boundary.

As Monastersky points out, markers could be from the Industrial
Revolution, or from the radioisotope signatures resulting from atmospheric testing
of nuclear weapons that ceased in the 1960s. While supporting the case for 1964
as the beginning of the Anthropocene, Lewis and Maslin [2] also put forward a
strong argument for using the measurable decrease in atmospheric carbon dioxide
between 1570 and 1620 (with a minimum in 1610), something that they relate to
the effects of New World colonisation and dramatic changes in human population
density, changes in diet and agricultural practices brought by new foods, and
the development of increased trade based on industrial production. Their selection
of 1610 adds another part to the Anthropocene debate, but their paper also contains
an interesting review of human impacts in the very short time that Homo sapiens has been the dominant
species on the Earth.

In conclusion, Lewis and Maslin write [2]:

Past scientific discoveries have
tended to shift perceptions away from a view of humanity as occupying the centre
of the Universe. In 1543 Copernicus's observation of the Earth revolving around
the Sun demonstrated that this is not the case. The implications of Darwin's 1859 discoveries
then established that Homo sapiens is
simply part of the tree of life with no special origin. Adopting the Anthropocene
may reverse this trend by asserting that humans are not passive observers of Earth's
functioning. To a large extent the future of the only place where life is known
to exist is being determined by the actions of humans. Yet, the power that
humans wield is unlike any other force of nature, because it is reflexive and therefore
can be used, withdrawn or modified. More widespread recognition that human
actions are driving far-reaching changes to the life-supporting infrastructure
of Earth may well have increasing philosophical, social, economic and political
implications over the coming decades.

Whether the Anthropocene should be defined, and what its
definition should be, seem trifling issues compared with those raised in that
last paragraph. Whether the Anthropocene began in 1610 or 1964, it has the
potential to be one of the shortest epochs thus far. The end of a geological
time period is usually marked by large-scale events such as asteroid impacts,
widespread upheavals in the Earth’s crust, or dramatic changes in climate. We
don’t know how the Anthropocene will end and it may be from one of these causes
and thus be outside human control. Alternatively, the epoch may end as a direct
result of human actions. We know how destructive we have already been, and continue
to be; with wars, global warming, widespread removal of forests, extinction of
populations, introduction of poisons and antibiotics, etc. all being major
impacts. There are those who feel that we should be able to overcome the many difficulties
we face using technological solutions but, while I admire human invention, I do
not feel optimistic about the future. The dominant economic system is based on
growth and growth cannot be sustained indefinitely, so those of us in the Developed
World will no longer be able to cocoon ourselves in warmed (or cooled)
buildings and we may need to hunt and forage to obtain food. The social crises
that result from a catastrophic fall in living standards can be imagined.

This is preachy, but our way of life, and its characteristic
complacency, is highly damaging for other organisms on Earth and, like all
the others, our epoch will end. The Anthropocene will be followed by another
epoch, but what organisms will dominate? After our controlling influence is no
longer present, the environment will again be the main vehicle for selection of
changes in genes (a natural mechanism that we override). Bacteria and other unicellular
organisms are sure to survive the cataclysmic events at the end of the
Anthropocene, but what about other organisms? Will evolution result inevitably in
a dominant form that makes drastic changes to its surroundings, or will there be
a less destructive solution to the relationship between organisms and their
environment?

Wednesday, 4 March 2015

In my last blog post, I wrote an appreciation of limpets and
the extraordinary adaptations that they show for life on rocky marine shores
[1]. As I pointed out, that should not prevent us from using these molluscs as
a source of food and that is something that fits with contemporary debates
about sustainability and the need for animal protein. We are now
much less resourceful than our ancestors, and are dependent on what is available
in stores or on market stalls, with the latter often showing a more local
approach than the former.

To gain an historical perspective on eating limpets, I read
Lovell's The Edible Molluscs of Great
Britain and Ireland with Recipes for cooking them [2] and he describes
their consumption by some communities:

"In many places limpets are used for food, especially
on the Continent, where they are oftener eaten than the periwinkle. At Naples
they make them into soup, and I am told it is an excellent dish.. ..The poorer
classes at Eastbourne eat them constantly.. ..At Plymouth they gather great
numbers of them, especially from the breakwater, as well as in the Isle of Man,
where they are known by the name of "flitters"; and in Scotland the
juice of these shellfishes is mixed with oatmeal.."

In addition to this background information, Lovell also
gives recipes [2]:

"Limpet Soup
– Wash them, and free the shells from seaweeds etc.; put them into a saucepan
and parboil them. Take them out of the shells; chop up some parsley, and put
it, with a tablespoonful of oil, or an ounce of lard or butter, into a
saucepan, and fry until it becomes brown. Add a pint of water, and, when
boiling, throw in the limpets, with a teaspoonful of anchovy sauce, some pepper,
and boil again for half an hour; or, if preferred, stew them before putting
them into the soup.

Limpet sauce –
Choose clean-shelled limpets, not covered with barnacles, steep them in fresh
water, and then heat them in a close covered saucepan until they part easily
from the shells. They yield a rich brown liquor, in which, after being shelled,
they may be stewed for half an hour. Thicken the liquor with butter and flour;
strain and season with pepper, cayenne, and salt, and a slight flavouring of
lemon-juice or vinegar. The limpets, being tough and indigestible, are not
returned into the sauce."

The latter comment reminds us of the common failing of
over-cooking seafood of all kinds, something that one learns by trial and
error.

Lovell [2] also gives a more rustic approach to cooking
limpets, originating from the island of Herm in the Channel Islands, and
reported by Jeffreys in Volume 3 of his British
Conchology:

"Roasted limpets
- The limpets were placed on the ground, and laid in their usual position, and
cooked by being covered with a heap of straw, which had been set on fire, about
twenty minutes before dinner."

To these recipes can be added others from different parts of
the World (illustrations of each dish are given, with the URL to the web page
for each recipe):

It is only possible to eat limpets as a regular
part of the diet if one lives at, or near, the coast. For those who are
landlocked, Lovell guides us to Garden Snails, together with their close relatives,
including the Roman, or Vine, Snail (and who doesn't like Escargots à la Bourguinonne?). Limpets and land
snails are both sustainable foods and provide good sources of animal protein.
Although I don't feel comfortable about roasting them alive, placing the
molluscs in boiling water kills them rapidly and they can also be kept in a
deep freeze for a short time to reduce their metabolism severely before they
are cooked.

Mark Zuckerberg became famous not only for Facebook, but
also for his statement that killing animals oneself is better than willingly
being ignorant of how we obtain the meat we buy from butchers or supermarkets
[3]. For those that would like to follow Mr Zuckerberg's example, but cannot
face the prospect of cutting the throat of a pig or a goat, killing snails of
various kinds provides rather less of a challenge.